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On 05/20/2011 01:12 PM, Cal Heldenbrand wrote:
<blockquote
cite="mid:BANLkTikOCbD8-w8mSF7OonmWX_NtSDY6mQ@mail.gmail.com"
type="cite"><br>
<br>
<div class="gmail_quote">
<blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt
0.8ex; border-left: 1px solid rgb(204, 204, 204);
padding-left: 1ex;">
First look in /var/log/libvirt/qemu/<domainname>.log and
see which qemu binary is being executed by libvirt - it may
not be the one you've built.<br>
</blockquote>
<div><br>
It looks correct... I pulled out the driver tag from my
config and fired it up. Here is the full command line for it:<br>
<br>
<span style="font-family: courier new,monospace;">LC_ALL=C
PATH=/sbin:/usr/sbin:/bin:/usr/bin:/usr/local/sbin:/usr/local/bin
QEMU_AUDIO_DRV=none /usr/local/bin/qemu-system-x86_64 -S -M
pc-0.14 -enable-kvm -m 4096 -smp
7,sockets=7,cores=1,threads=1 -name web101 -uuid
bda63821-ccc4-6607-67c0-db6712526cbd -nodefconfig
-nodefaults -chardev
socket,id=charmonitor,path=/var/lib/libvirt/qemu/web101.monitor,server,nowait
-mon chardev=charmonitor,id=monitor,mode=readline -rtc
base=utc -boot c -drive
file=/var/lib/libvirt/images/web101.img,if=none,id=drive-virtio-disk0,format=raw,cache=writethrough
-device
virtio-blk-pci,bus=pci.0,addr=0x5,drive=drive-virtio-disk0,id=virtio-disk0
-drive
file=/home/httpd.img,if=none,id=drive-virtio-disk1,format=raw,cache=writethrough
-device
virtio-blk-pci,bus=pci.0,addr=0x7,drive=drive-virtio-disk1,id=virtio-disk1
-drive
if=none,media=cdrom,id=drive-ide0-1-0,readonly=on,format=raw
-device
ide-drive,bus=ide.1,unit=0,drive=drive-ide0-1-0,id=ide0-1-0
-fsdev
local,security_model=passthrough,id=fsdev-fs0,path=/home/httpd
-device
virtio-9p-pci,id=fs0,fsdev=fsdev-fs0,mount_tag=/home/httpd,bus=pci.0,addr=0x8
-netdev tap,fd=15,id=hostnet0 -device
virtio-net-pci,netdev=hostnet0,id=net0,mac=52:54:00:6f:51:43,bus=pci.0,addr=0x3
-chardev pty,id=charserial0 -device
isa-serial,chardev=charserial0,id=serial0 -usb -device
usb-tablet,id=input0 -vnc <a moz-do-not-send="true"
href="http://127.0.0.1:0">127.0.0.1:0</a> -vga cirrus
-device AC97,id=sound0,bus=pci.0,addr=0x4 -device
virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x6</span><br
style="font-family: courier new,monospace;">
<br>
<br>
</div>
<div> </div>
<blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt
0.8ex; border-left: 1px solid rgb(204, 204, 204);
padding-left: 1ex;">
Then, run "qemu-kvm --help" (replacing "qemu-kvm" with the
path to the binary that libvirt is executing, found in the
previous paragraph), and search through that output for the
string ",vhost=" - if it's not there, then your qemu doesn't
support vhost-net.<br>
</blockquote>
<div><br>
This also looks correct. Is it wrong that my qemu compilation
didn't create a binary named "qemu-kvm"? (Even though it said
"KVM support yes" on the configure output?)<br>
</div>
</div>
</blockquote>
<br>
Not exactly, but close. In the qemu capabilities code, there is a
variable called "is_kvm" that is only set if it finds the string
"(qemu-kvm-" or "(kvm-" in the help output. It seems to me that this
used to be used for a lot more things, but when I look now I see
that it's used for very few things (maybe a result of the
capabilities code refactoring, or maybe my memory is faulty :-).
However, one of the things still in place is that
QEMU_CAPS_VNET_HOST isn't set unless is_kvm is true.<br>
<br>
I believe this dependency on is_kvm is there because someone said
that the feature was only in kvm, but retrospectively that doesn't
make sense. Can you try building with the following patch, and see
if that works?<br>
<br>
diff --git a/src/qemu/qemu_capabilities.c
b/src/qemu/qemu_capabilities.c<br>
index ea55df5..71a54a5 100644<br>
--- a/src/qemu/qemu_capabilities.c<br>
+++ b/src/qemu/qemu_capabilities.c<br>
@@ -982,7 +982,7 @@ qemuCapsComputeCmdFlags(const char *help,<br>
if (is_kvm && (version >= 10000 || kvm_version >=
74))<br>
qemuCapsSet(flags, QEMU_CAPS_VNET_HDR);<br>
<br>
- if (is_kvm && strstr(help, ",vhost=")) {<br>
+ if (strstr(help, ",vhost=")) {<br>
qemuCapsSet(flags, QEMU_CAPS_VNET_HOST);<br>
}<br>
<br>
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